ROCKFORD — Police union leaders say the city is preventing them from gathering information they need to make their case against Chief Chet Epperson in a hearing with the Rockford Board of Fire and Police Commissioners.

The Police Benevolent and Protective Association Unit 6, through Rockford attorney Dan Cain, filed a motion Thursday to force the city to turn over records it requested through a subpoena. The union released the motion to the press today.

The motion is the latest legal maneuver in the union’s attempt to seek disciplinary action against the chief for his involvement in a welfare check Oct. 30, 2013, at Lloyd Johnston’s residence. Johnston, who is NAACP Rockford’s branch president, called Epperson’s cellphone after police arrived at his home. Epperson sent a supervisor to the house in response.

A probable-cause hearing in the matter is scheduled for July 21.

The union wants to obtain police reports, officers’ notes, a memorandum about the incident, human resources notes and other materials relative to the welfare check, Cain said.

According to the motion:

— Subpoenas for the materials were issued June 16, but City Legal Director Patrick Hayes has refused to turn them over.

— A motion to quash the subpoenas was denied June 23.

—Hayes said the materials requested are private and would not be subject to disclosure under the Freedom of Information Act.

The materials “contain all the information relative to the charge in the complaint,” Cain said in a telephone interview. “In addition, we believe that after the event Chief Epperson attempted to order responding officers to change their police reports.”

Hayes said in a phone interview that the material requested by the union has been turned over to the Fire and Police Commission’s hearing officer, attorney Ian Linnabary, for his review. He said the union has requested material that is privileged and should not be disclosed publicly.

A hearing on the motion to partially quash the subpoena is scheduled for 4 p.m. Tuesday.